He talked to trekmovie.com
http://trekmovie.com/2008/07/15/jumpcon-series-in-serious-doubt-celebrity-guests-not-planning-to-attend/#more-2161 Senter tells TrekMovie they had sold 500 tickets for the Boston event (and many more for future events). He said their policy would be to provide full refunds within 14 days to anyone who requests one, but when pressed he admitted that "as of this moment" they did not have the funds to provide the refunds. Senter stated that the funding he is seeking now is for both paying celebrities and dealing with potential refunds. He also admitted that if the Boston convention does get canceled he would likely have to cancel the remaining JumpCons, saying "who would buy from me after this?"
He just sent someone this message
"We are putting the pieces back together and will have a new revamped
program with everything in place - We started refunding and there were
some
of the tickets that got refunded because people a human and that mistakes
happen - She was given a list and started to do the refunds off the
list. We
will have more updates by Friday as to the other events and what we
can do to
make this up to everyone - Shane"
He says that BOSTON is the only convention affected by the cancellation.